AT&T Next vs iPhone Upgrade program vs AT&T 2 year contract.

Currently, my mom and I are on a family plan. We have alternating upgrades and so every year, I get the new iPhone and I give her my current iPhone. This year, her line is available for upgrade and so I will be taking that upgrade and giving her my iPhone 6. Wanted to ask, taking into consideration upgrading every year, should I stay with the 2 year contracts, choose At&t next, or Apple iPhone upgrade program? Reason why I ask is because all of these montly plans are confusing to me. If anyone could help, thatd be appreciated. Our AT&T bill is currently $155. $100 for 15gb of data, unlimited talk, unlimited text. $15 for line access (moms number, the upgradeable line), $40 for my line.

Since this involves a family member that you are in a family plan with it is in your best interest to contact your current carrier and see what is the very best you can get right not from them and discuss it with your mom as opposed to us since it would be tough for us to answer that. Might not even hurt to contact another carrier to see if they can do better and pay for the switch over. Good luck.